Brush head of a toothbrush



FIG. 1 is a top plan view of a brush head of a toothbrush showing the new design;

FIG. 2 is an enlarged, fragmentary, top plan view showing the design of the bristles thereof;

FIG. 3 is a side view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a first end view thereof; and,

FIG. 6 is a second end view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a brush head of a toothbrush, as shown. 